Productive Things
by RaversAnthem
Summary: MxGxF Smutty smut smut. Marshall Lee is tired of waiting, because Fionna won't be around forever.


**A/N:** Alright. I wasn't finding any satisfying smut for these three, so I decided to write one. Warning- this ain't no smut-light story. This is as down and dirty as it gets.

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" _Marshall Lee Abadeer_ , you will take back what you said about Fionna right this minute or I'll... I'll..."

"You'll what, Beau? Sick your Banana Guards after me?" Marshall smirked from where he lay sprawled on Gumball's bed. Prince Beauregard Gumball, for all the naturally pink tones he already boasted, was flushed a charming shade of red as he stared in horror at the Vampire King lounging on his bed. "I only came here to talk to you because we've got a long history together. We're friends!" he paused, smile stretching just noticably wider, "She's got feelings for both of us, Bubba. I thought you had feelings for her too... but if you don't then I'm not going to feel bad swooping in-"

"I never said I did not feel anything for Fionna, but what you are suggesting is base, and impolite, and despicable, and-"

Marshall flipped from his back to crouch on his hands and knees on the bed, "Not another word, Beauregard." he hissed.

Gumball, surprised, took two steps back before he realized what he was doing. Frowning, he straightened his shoulders and met Marshall's gaze with a glare of his own. "Your suggestion is brash, uncouth, unnatural, and... and disgusting!" he snapped.

Marshall's face twisted into a snarl, his fangs lengthening and his face partially morphing into a monstrous bat. Before Gumball could blink, the Vampire King had disappeared from the bed and materialized across the room, shoving Gumball roughly up against the wall. Still angry, Marshall's face had lost the bat-like features but kept the thunderous glare as he stood nose to nose with the candy prince.

"Listen to me, Beauregard, because I'm only going to say this once: sexual desires are neither unnatural or disgusting. You and I are millennia old; you cannot tell me you've never been sexually curious. I know you too well." Marshall's breath blew hot streams across Gumball's skin, his hands manacled Gumball's wrists to the wall, and his thigh pressed between Gumball's legs.

Despite retaining the free movement of his head, Gumball couldn't look away. "She's too young for you, Marshall."

"Us."

"Us?"

"If she's too young for me, Beau, then she's too young for you."

"Oh." the Prince replied lamely.

"She's not too young, Bubba. She's all grown up, and she's nothing like us. We both know what she is, and the truth is neither of us knows what's going to happen. Outside of Fionna and her Mother, when was the last time you saw a human? Or, better yet, when was the last time you saw a human live out their life? Because I can't remember, Bubba, and that's scary as fuck. She's not going to be around forever, and you and I could fight until the stars have all burned up in the sky and it will be too late. I don't know about you, but I don't want to waste another minute bickering when we could be doing much more... productive things."

Gumball swallowed loudly, his mouth dry. "What you're suggesting though, Marshall, is... is... depraved." he argued, but Marshall caught the slight dilation of his pupils, and his mouth slightly parting. His face was still flushed, and his breath was coming in short puffs. Marshall's expression softened, and his smile slowly returned as he reveled in his victory. He released the Prince's wrists and pressed forward only slightly more until his thigh ground against the hardening erection in the Prince's pants. Gumball shivered and gasped.

"C'mon, Beau." Marshall continued, "We've both been with women, and being with another man isn't unusual for either of us either. It's no stretch to do both at the same time... And you and I? We have history. I wouldn't mind making some more with you." It was time for the coup de grâce, the confession. He leaned in and ran his tongue along Gumball's bottom lip. "She finds the idea a total turn on, I promise, Bubba."

"H-how do you know?" Gumball blinked once, twice, and his eyes cleared as he seemed to come back to himself a little.

Marshall chuckled and shifted, nipping at the Prince's jaw and moving to his ear, "I asked her."

Gumball's eyes widened to saucers and the voice that escaped him was octaves higher than his usual tenor, "You WHAT!?" Arms free, Gumball shoved at the vampire, only succeeding in separating them by a few short inches.

Marshall's smile didn't disappear this time though, "I asked her. Kind of." he repeated, unrepentant.

"I- What- You... You can't just... You didn't... She... Marshall, what exactly did you ask Fionna?!" Marshall could tell Gumball was trying very hard to press his features into a frown, but he couldn't seem to control himself as his eyes remained wide, eyebrows raised in surprise. Gumball's jaw, though, was clenched and Marshall realized there was no more beating around the bush.

Marshall shrugged, rolling his eyes, "When she was over last week I told her someone called us an old married couple and asked if we'd been caught bangin' in the castle yet, and I asked her if she could believe it."

"An old married- Bangi- what?" Gumball repeated.

"Beau, you should have seen her face! She thought she was hiding it well but Fionna couldn't hide a needle in a haystack. Her eyes were so wide I thought they'd pop out, but it was more than surprise." Without warning, Marshall pressed back in until they were pressed flush once more, "Her hands were doing that thing where they don't know what to do with themselves. She crossed her legs and uncrossed them and crossed them again, and..." his hands found their way under Gumball's shirt until they met flesh. Against Marshall's hands, the Prince felt like an inferno.

"And...?" Gumball repeated the word on a gust of breath, the surprise slowly dissipating from his features and his lids dropping as his gaze focused on Marshall's mouth.

Marshall nipped at the Prince's chin and moved to his neck. "She got all red and stuttery and pretty much ran from my place, so I followed her home..." he pressed a kiss to Gumball's neck, letting his fangs scrape across the skin. The collar of the Prince's shirt wouldn't allow him to go any further, but he ignored his annoyance for the moment.

"Home..." Gumball groaned, eyes sliding shut.

"Mmhm. So I followed her. Damn, Bubba, you would not believe what she left to do." Marshall pressed his advantage, lifting Gumball's shirt higher until he felt a nipple under his fingertips. Gumball gasped, his fists clenching, so Marshall flicked the nipple again. "Ask me what I caught her doing, Bubba."

Gumball's face was flushed, his cock ramrod straight as he ground his hips against Marshall's. His breath was coming in short gasps, but his eyes fluttered open briefly as he registered the question. "What?"

Marshall bit back a moan of his own and met Gumball's hips. "I gave her a bit of a head start. She may not be good at hiding things, but she's pretty damn good at knowing she's being followed. When I finally caught up with her, she'd made it all the way home..." Marshall's fingers worked into Gumball's belt, tugging at the clasp, "... and she was up in bed. Lucky girl, Cake wasn't home. Mmmm, don't stop." he hummed appreciatively as Gumball lifted his hands to roam over Marshall's chest. "Oh, Bubba, what she was doing in that bed... I didn't even know she knew a damned thing about it." Gumball's belt was finally undone and Marshall made quick work of his pants' button and zipper, "... but there she was, lying back on her bed with her panties around her ankles and her skirt all hiked up, legs spread..." Marshall's hand slid into Gumball's pants and the Prince squirmed as he felt it grip his erection.

"Marshall!"

The Vampire King groaned, pumping Gumball's cock in slow, torturous strokes. "Her hand was between her legs and she was finger-fucking the sweetest little pussy I have ever imagined."

"Fionna?" Gumball's hands, which had been pulling Marshall's shirt upwards, paused.

"Yes, Bubba, our little Fionna. Sweet, innocent, naive, darling Fionna had her fingers deep inside her pussy, fingering herself like there was no tomorrow." The hand that wasn't occupied with Gumball's penis tugged at the waistband of his pants, pulling them down his hips. "And that's not even the best part. She was gettin' off and panting and thrusting those sweet little hips into the air _as she screamed our names_. Both of us, Bubba. She wants both of us... and I say we give it to her."

Gumball's hips jerked at the image, "Fuck, Marshall-"

Marshall pulled away and yanked his shirt off before sliding to his knees and taking in the sight of Gumball's dick. Hard, it jutted stiffly upward. The head was a desperate red and the very tip leaked precum. Marshall wrapped his hand around the base again, licking his lips. His other hand slid over Gumball's hip and around to his ass, tracing downward until he found the ring of muscle that was Gumball's opening. "So I invited her here." Marshall's voice was carefully level, but Gumball's eyes snapped open and he stared down.

"Invited her over for when?"

Marshall probed gently at Gumball's ass, but did not answer the question.

"Marshall, when did you in-"

Marshall surged forward, engulfing Gumball's penis in one long swallow as his finger simultaneously buried itself in his ass. The heat from Marshall's mouth paired with the invasion of his finger stopped Gumball mid-sentence and instead his eyes slid closed and a strangled shout escaped his mouth.

Both men were interrupted at that moment by a crashing noise as the doors to Gumball's bedroom flew open and slammed noisily against the wall. Gumball's head whipped to look at the intruder, but Marshall only paused before continuing his ministrations.

It couldn't have been anyone else. Fionna stood at the ready in his doorway with her sword drawn and a battle-ready expression. She scanned the room until her gaze rested on them and her eyes widened.

"Oh!" she exclaimed, her sword arm going limp. "Oh my Glob- Marshall, Gumball, I had no idea you were, um, were... occupied. I'll just... you know... leave." she took a slow step back, but her eyes never left the two of them.

Suddenly, his dick was cold and Gumball looked down to find Marshall was gone. When he looked up, he found the shirtless vampire had blinked over to Fionna faster than he could track. He now stood behind Aaa's heroine, his hands gripping her hips and his lips tracing her her hat where he knew her ear was. "Uh uhn, Fi, you don't have to leave..."

Fionna froze, but her face flushed a deeper red and her gaze had locked onto Gumball's penis now that she could see the entire length. "I... I don't?" she repeated, her voice trembling.

Marshall's hands slid upward from her hips, pulling the hem of her shirt with them and revealing pale skin in their wake. "I was just telling Beau here how much you... enjoyed the idea of Beau and I fucking in the castle." his gaze flicked up and he met Gumball's eyes and his mouth turned into a fang-baring smirk.

"Fucking?!" Fionna squeaked as her face somehow reddened more.

"Mmmmhm. I was just telling Beau here how I found you after we had our little talk last week, how your legs were open and your pretty pink lips were spread as you rode your own fingers and called our names." Marshall's hands lifted her shirt over her breasts before cupping both through her bra.

Suddenly Fionna was looking anywhere but at the two men. She stuttered as she tried to form a rational string of words to use as a sentence and failed.

"Fionna?" her gaze snapped up to meet Gumball's as if helpless to do otherwise. He was staring at her from his position against the wall. He'd given in to the feeling and his own hand was wrapped around his cock now, pumping slowly as they both stared. After a long pause, the Prince wet his lips, "Do you want to touch me?"

A garbled squeak managed to escape Fionna's lips, and Marshall chuckled, "I think that was a 'yes', Bubba." he let go of her breasts and tugged the hat off of her head. Blonde locks slipped from their confinement to tumble over her shoulders. This seemed to draw Fionna back to her senses as she pulled her gaze from Gumball and jerked away.

"I- what- why- IinteruptedI'msosorryI'lljustexcusemyself." she blurted, spinning to dodge out of Marshall's way. Marshall moved with her, capturing her wrists before she could try again. He pulled at her arms, turning her to face the Prince again.

"You're not interrupting." his voice caressed her ear and ruffled her hair. "Look at Beau, he's hard for you." Marshall pressed his erection to her backside, "I'm hard for you."

"But, uhm, you were just... I mean isn't what you were just, uhm, doing why he's... how he is?" Fionna bit her lip, trying desperately not to grind back against the Vampire King's hips.

Gumball pushed away from the wall, his pants slung low and his dick standing straight out as he moved towards the paid. His face was flushed with desire, but there was a hint of nervousness in his gaze, "Didn't you hear what Marshall said, Fionna?" he stopped almost close enough that she could reach out and touch him. "I'm turned on, hard as a jawbreaker, because Marshall caught you masturbating to us." he ran his hand slowly up his dick, running his thumb over the tip as he reached it.

"Truth is, Fi, we both want you." Marshall ran his tongue down Fionna's neck to her shoulder. "We know you have feelings for us both, and we wouldn't be opposed to... sharing."

"If you would have us." Gumball clarified. Marshall mumbled agreement as he nipped at her shoulder.

"How would you, uhm... share?" Uncertainty still coloured her voice, but she watched Gumball's hand raptly and she shifted from one foot to the other.

Marshall chuckled and gave her a little shove forward. "Go touch Beau, Fi."

Fionna stumbled forward, Gumball catching her by her shoulders before she could completely fall. She didn't meet the Prince's gaze, however. Her eyes were locked on the length of his dick. It was dark pink, the head almost red, and shiney with Marshall's saliva. Tentatively she reach out a hand until her fingers brushed the head. Gumball let out a low groan, watching her hand intently as it pulled back briefly before reaching out again. This time her fingers ran down the side of his shaft and back up. Gumball shuddered. The touches were hesitant and light- in short, tortuous.

Chuckling, Marshall pressed into Fionna's back again. "Let me show you how out Prince likes his cock stroked." Fionna made a wordless squeak as his hand slid over hers and took control. He wrapped both their hands around Gumball's penis, stroking up from the root and over the head before rpeating the motion. Unable to control it anymore, Gumball's eyes slid closed and his head lolled back. Fionna bit her lip as she glanced up at him, her breaths coming in little, gasping pants. Marshall's hand carressed up Fionna's stomach once more as he encouraged her.

"Just like that, Fi. Run your thumb over the head. Fuck, looks delicious, doesn't it? I bet you want to wrap your mouth around his cock, don't you?" When Fionna nodded in agreement, he felt his own cock pulse in his pants. "Good girl." he praised, his hand reaching her breasts once more. "Let me reward you." Marshall's fingers slipped under the middle of her bra, sharpening to claws before he gave a pull. The fabric sliced cleanly in two, baring two pale breasts with soft pink nipples hardened into little points. Marshall groaned and Gumball lifted his head to see. "What d'ya think, Bubba?"

Gumball's eyes focused on the nipples rising and falling with each panting breath and he licked his lips. "Amazing..." he murmured, startling Fionna into tearing her gaze away. She flushed and lifted her hands to cover herself but Marshall caught them first.

"Ah, ah, ah Fionna. Don't you dare cover up those fantastic breasts."

"Fan-fantastic?" she stuttered.

"Mmhm. Definitely. Best I have ever had the pleasure of seeing. What about you, Bubba?" Mourning the loss of her hand but unable to tear his eyes away, Gumball only nodded before leaning forward.

"G-g-gumball what are yo-" she gasped, arching back as Gumball wrapped his mouth around one nipple. Her eyes slid closed and her head fell back onto Marshall's shoulder. She flexed her hands, whimpering, and when Marshall let her wrists go she latched onto Gumball's shoulders, trying to draw him closer.

Marshall groaned, "I seriously underestimated how incredibly hot this would be." he dropped his head to lick and suck at her neck. Fionna's soft gasps and whimpers urged him on as he gripped her shirt and tugged, It caught on her hips, unwilling to go any further, and he hissed his displeasure against her neck before tearing the fabric. As Gumball moved to her other breast, palming the first, Marshall pressed his erection against her panty-clad ass and ground against her. The second time he thrust he moaned as she pressed back against him. She turned her head and Marshall lifted his face from her neck to gaze into her heavy-lidded eyes. She wasn't focused on his eyes, though. Her tongue darted out across her lips as she focused on his mouth.

"Marshall?" she watched those lips quirk, revealing fangs, "Kiss me."

He didn't need to be told twice, and covered her mouth with his. He nipped at her lips before soothing them with his tongue. When her tongue tentatively met his, he pressed further, invading her mouth and taking over. Gumball let go of her nipple and guided her to face Marshall as they kissed. He tugged at the shirt still bunched around her breasts and she lifted her arms, only allowing the kiss to stop for long enough to completely remove it then removed his own as well. After that Gumball tugged free the remnants of her bra and nipped at her shoulders, kissing his way down her back. Fionna gasped as he made his way down the sensitive plains of her back, allowing Marshall to kiss her even deeper. She felt Gumball's hands grip her hips as he nuzzled along the line of her panties and felt her legs tremble in response. Her hands pressed against Marshall's chest, running over the muscles, tentatively touching his nipples. Marshal groaned, capturing her hands in his again. This time, however, he guided them down, settling them on the waistband of his pants. Fionna fumbled with the button and zipper, but soon had them undone so she could tug them down.

Never having been one for underwear, Marshall had nothing left preventing his cock from announcing itself. Fionna gasped as she felt it slap against her stomach. She pulled away to look down and her eyes widened. "Oh..." she squeaked, stepping back into Gumball. He rose up behind her again, stopping her from escaping once more.

Marshall laughed at her expression, "Damn, Fi, you sure do know how to flatter a male." He left his pants fall the rest of the way, toeing his shoes off at the same time and stepping after her and closing her off. "Well, now that you've seen both of ours... what d'ya say we let Gumball see that hot pussy of yours, Fi?"

"My wh- my pu- my- my what?" Still stuttering? It was absolutely adorable paired with that blush.

Marshall flashed his fangs in a smirk and leaned down, swooping her up into his arms. Fionna let out another wordless cry, squirming as he carried her to Gumball's massive, four-poster bed. Sitting on the edge, he settled Fionna in his lap facing Gumball, who had followed them. Marshall's erection pressed insistantly into her ass and she wiggled against it, causing him to moan. Without a word, Gumball leaned over the pair and took her mouth in a deep kiss, sliding his tongue against hers in a way that made her toes curl. Marshall's hands found her breasts, tugging at her nipples ruthlessly this time. As she reached for Gumball, to touch him anywhere she could, he batted her hands away.

Pulling back, they both panted as they stared at each other. Then Gumball smiled in a way Fionna had never seen. His lips curled slowly at the corners, his eyes heavy-lidded as he took in her flushed face. If she didn't know any better, Fionna would have said he looked like he was going to... to eat her.

Marshall's hands abandoned her breasts in favour of running up and down her thighs, over stockings and bare legs. Gumball took up her abandoned breasts, running his tongue over her hardened nipple before biting down. Surprised, Fionna arched with a gasp and gripped at the bedding instead. Marshall took the moment of distraction and slid his hands between her thighs and pulling them apart, exposing soaked panties. The cool air against her core made her shiver and wiggle, and Gumball moved down her body, kneeling in the floor before them. He pressed his nose to her core and inhaled. Fionna whimpered. Gumball sucked at her clit through the fabric and she moaned. Pink hands ran up the inside of her thighs to the waistband of her panties. Grey hands lifted under her ass as Gumball tugged them away. As Gumball pulled them down her legs Marshall's hands moved under and between her thighs, and once divested of them he spread her legs- and subsequently her pussy.

"Fuck."

Startled, her eyes flew open to see Gumball staring at her. She had never heard him utter a single curse in all the years that she'd known him, but one look at her swollen sex had caused him to forget his usual rigidity. Fionna flushed so much that it was a wonder she had any blood anywhere else as she watched him lean forward. His gazed flicked up to meet hers and there was something wicked in it.

"Spread yourself for me, Fionna." She could feel his breath ghost over her flesh as he spoke. Mesmerized, her trembling hands released the blankets and moved down to her sensitive labia. Gumball nuzzled her hands as she slowly spread her lips to reveal the rest of her pink flesh. Without hesitation he closed the distance and ran his tongue up her slit to flick her clit.

"Gumball!" her hips jerked, causing her to grind against Marshall's cock. His grip on her thighs tightened and he thrust back.

"Fuck, she liked that, Bubba."

Gumball chucked before suckling her clit. Fionna cried out again, squirming against Marshall's hold. Gumball groaned against her flesh, fisting himself and pumping his member roughly. Abandoning her clit, he thrust his tongue into her tight opening, mimicking the thrust of a different limb. She squeezed around him as he did, panting and moaning softly.

"Gumball- please- I-"

Marshall leaned into her ear, "What do you want, Fi?"

"I want... I don't..." she turned her head, burying her face in his neck as she squirmed against them. Gumball worked at her pussy, licking and sucking every inch of flesh his mouth touched.

"Do you want Bubba's dick?"

"Yes!"

"You want him to fuck you with it?"

"Oh my Glob, please!"

"Say it, Fionna."

"Please, Gumball, I need you to- to-"

"To what, Fionna?" Marshall urged as Gumball pulled back. His lips were wet as he met Marshall's gaze. Both males shared a knowing look.

"Whatever you need is yours, Fionna- you need only ask."

Fionna peeked from where she'd hidden her face, eyes locking onto Gumball's penis. She moaned, "Gumball, I want- I need to cum! Please!"

Gumball needed no other prompting. He sucked roughly at her clit. Without warning, he slid two fingers into her and curled them. Fionna's back bowed, her heels digging into Gumball's shoulders. She clamped down around his fingers and came with a wordless cry. Gumball licked ruthlessly, thrusting his fingers into her until she cried out in protest and slumped bonelessly back against Marshall.

"Oh, Glob..." she breathed, panting.

Both males chuckled. "We aren't done yet, Fi." Marshall warned.

"We're just getting warmed up." Gumball agreed.

* * *

 **A/N:** Wow. That ended up waaaay longer than intended. And that's not even where I intend to finish... Man, this was supposed to be a oneshot!


End file.
